In general, for attitude change control with respect to a flying object having a flexible member, such as an artificial satellite, it is required, in many cases, that changing to a desired attitude be performed quicker and with higher accuracy. In such cases, the most problematic is the vibration of the flexible member. If the flexible member is vibrated due to the attitude change, the vibration is transmitted onto the main body of the flying object, causing an error in orientation of the main body. In addition, once the vibration has occurred on the flexible member, it takes a considerable amount of time for the vibration to attenuate. As can be seen from the above, with regard to the attitude change control of the flying object having the flexible member, a major challenge is how to suppress the vibration of the flexible member.
For example, JP 3623747 B (Document 1) discloses an attitude change control method for a three-axis-stabilized satellite or the like as technology relating to the attitude change (attitude control) with respect to an artificial satellite or the like. With this attitude change control method, when an attitude control target value is created, frequency separation is not performed with respect to frequency components included in the target value. As a result, it is impossible to prevent the flexible member (artificial satellite flexible moving unit) mounted on the artificial satellite or the like from being excited, and constant vibration of the flexible member lingers on even after the maneuver is completed. To be specific, after the maneuver is completed, a settling time for attitude stabilization (subsiding of vibration) is required before an observation mission is ready to be started. Accordingly, because orientation stability cannot be secured until the vibration subsides, the observation mission cannot be started. Consequently, the entire time (period of time from start of attitude maneuver to start of observation mission) required for the attitude maneuver becomes long.
Therefore, there have been proposed measures for suppressing the vibration of the flexible member at the time of the attitude change control. Examples of the measures include: an attitude maneuver control method for a flexible satellite by means of bang-bang control, which is proposed by N. C. Singer et al. (Document 2: see “Singer, N. C., Seering, W. P.: Preshaping Command Inputs to Reduce System Vibration, Journal of Dynamic Systems and Measurement Control, 112 (1990), pp. 76-82”); and an attitude maneuver control method for a flexible satellite by means of the bang-bang control, which is proposed by B. Wie et al. (Document 3: see “Liu, Q., Wie, B.: Robust Time-Optimal Control of Uncertain Flexible Spacecraft, Journal of Guidance, Control, and Dynamics, 15 (1992), pp. 597-604”).